This study is designed to demonstrate the feasibility of producing erythropoietin from human kidney cells in culture. At present, the only commercially available source of human erythropoietin is from the urine of aplastic anemics. Humans cells in culture represents an excellent alternative source for human erythropoietin. If erythropoietin can be economically produced from human cells in culture, it could serve as the primary source of this hormone. Cell culture has the inherent advantages of ease of production cost-effectiveness and quality of product. It also eliminates the problem of unidentified contaminants associated with products derived from human blood or urine. A high quality, inexpensive cell culture-derived EP could satisfy the estimated yearly market potential of $180 million for treatment of erythropoietin-deficiency anemias. The objective of phase I of this study is to screen candidate human kidney cells for their ability to produce EP under normal and induction conditions. Initially, six kidney cell lines will be screened for constituitive EP production and secretion. Based on these studies, the highest producers will be further studied using nine induction procedures. Through these experiments, we hope to define the best EP producer cells for eventual large scale production of human EP. In our screening studies, EP production will be quantitated by measuring 59Fe incorporation into rabbit bone marrow cells.